Jack



N. A. BOYETTE April 1, 1930.

JACK

Filed April 24, 1928 Y 3mm Mdfiayeffa MP Z2 30 z/ Patented Apr. 1, 1930 NOAH A. BOYETTE, F HAHIRA, GEORGIA JACK Application filed April 24, 1923. Serial No. 272,515.

This invention relates to jacks and more particularly to a jack for holding saw logs or other heavy timbers in an elevated position.

An important object of the invention is to provide a device of this character which may be very readily attached to the log and which provides an eflicient means for raising the log and holding it in an elevated position.

A further object of the invention is to provide means of this character including apparatus for holding the log against movement while an operation is performed thereon.

A still further object of the invention is to 15 provide a novel operating means for the hoisting mechanism permitting the movement of the hoisting mechanism to be reversed to lower the log when the operation is completed.

These and other objects I attain by the construction shown in the accompanying drawing, wherein for the purpose of illustration is shown a preferred embodiment of my in vention and wherein Figure 1 is. a side elevation partially in section of a jack constructed in accordance with.

my invention;

Figure 2 is a section on the line 22 of Figure 1;

Figure 3 is a section on the line 33 of Figure 1.

Referring now more particularly-to the drawing, the numerals 10 and 11 indicate upwardly converging side members which 35 are secured together at their upper ends and at their lower ends are provided with shoes 12 affording a broad supporting surface. At a point spaced from the upper ends of the members, the opposite side faces thereof are connected by transversely extending braces 14' so that the completed structure comprises an A-frame in which the cross bar is formed of spaced elements. The legs or side members 10 and 11 are preferably constructed of channel iron.

Slightly to one side of the center of the braces, they are connected by a spacing and guide block 15 against which operates the toothed face of a rackbar 16 which extends between the braces. A roller 17 supported by the braces 14 engages the rear face of this rack bar and the upper end of the rack bar is guided by the edges of an opening 18' formed in the leg 10. The lower end of this rack bar has pivoted thereto cant dogs 19 to engage opposite faces of the timber. Pivoted to the leg 11 adjacent the upper end thereof is a link 20, the lower end of which I has pivoted to opposite faces thereofapair of bars 21, the opposed faces of which are spaced apart a distance equal to the width of the rack bar and the inner endsof which are connected by a pin 22 adapted to engage in the teeth of the rack bar. The outer ends of the bars 21 are connected byyoke' straps 23 adaptedto receive the end of a handle lever 24 by means of which the lever formed by the bars 21 may be oscillated to cause the engagement of the pin 22 with different teeth of the rack bar.

Pivoted to the leg 11 above the lever 21 1s a holding pawl 25 for engagement'wlth the teeth of the rack bar. This pawl has a tall 26 which is connected to one end of a spring 27, the opposite end of which is connected to the leg '11 near the top thereof. This ta1l also has means for detachably connecting therewith one end of a spring 28, the lower end of which is permanently connected with the lever 21.. Pivoted to the leg 11 adjacent the lower end thereof is an arm 29, the upper end of which has pivotally connected thereto a segment 30 extending through an opening formed in the leg 11 and having teeth 31 on its lower face for engagement with an edge of this opening, so that the arm 29 may be held in adjusted positions.

In the use of the device, the A-frame is placed across the log and the cant dogs 19 engaged with the side faces thereof. During raising operations, the spring 28 is disconnected from the pawl 25, the spring 27 alone acting thereon. \Vith this arrangement of the parts, if the lever 24 is oscillated, the pin 22 engaging with the teeth of the rack bar will cause the rack bar to be elevated and it will be held in its elevated position by the pawl 25. When the desired elevation has been attained, the arm 29 can be shifted inwardly until it engages the log and holds the same against oscillation. When Work upon the log has been completed, the spring 28 is connected with the tail of the dog. With parts in this position, when the handle 24: is forced downwardly, the spring 28, which has a normal tension equal to that of the spring 27, is given a greater tension, with the result that the pawl 25 is withdrawn and held withdrawn as the lever is elevated. This condition continues until the'tension of the spring 27 exceeds that of the spring 28, when the pawl will reengage with the rack bar and support the same while the pin 22 is being shifted to a lower notch It will be obvious that apparatus of this character may be very readily and cheaply constructed and may be made verystrong and capable of handling heavy loads without being made of an excessive weight; It will also be obvious that certain changes are possible in the construction without materially departing from the spirit of the invention and I accordingly do not limit myself to such specific structure except as hereinafter A jack comprising a standard, a rack bar, an actuating lever pivoted to the standard and adapted to engage the teeth of the rack 30 bar with its inner end, a pawl pivoted to the standard and having a tail, a spring engaging the tail of the pawl and secured .to the: standard and urging said pawl into engagement with the teeth of the rack bar, and a 35, spring connected with said lever and connectible to the tail of the pawl, said spring when connected to the tail of the pawl overcoming the tension of the first named spring to maintain the pawl out of enga ement with the teeth of the rack bar until the inner end of the lever has-been lowered to a predetermined extent. 7 a

In testimony whereof I hereunto afiix my signature. :3 NOAH A. BOYETTE. 

